sunxi: musb: Fix some lo speed devices not working with musb host

The usb0 / otg phy on sunxi boards has a bug where it wrongly detects a
high speed squelch on usb reset deassert when a lo speed device is plugged in.

The android kernel has a work around for this in the form of temporary
disabling the phy's squelch detection on reset deassert, this commit adds
the same workaround to the u-boot sunxi musb code, thereby fixing various usb
lo speed devices not working.

Tested with a (before non working) usb keyboard and a usb 2.4 GHz wireless
keyboard/mouse combo receiver.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>

arch/arm/cpu/armv7/sunxi/usbc.c

@@ -182,6 +182,13 @@ static void sunxi_usb_passby(struct sunxi_usbc_hcd *sunxi_usbc, int enable)
 	return;
 }
 
+void sunxi_usbc_enable_squelch_detect(int index, int enable)
+{
+	struct sunxi_usbc_hcd *sunxi_usbc = &sunxi_usbc_hcd[index];
+
+	usb_phy_write(sunxi_usbc, 0x3c, enable ? 0 : 2, 2);
+}
+
 int sunxi_usbc_request_resources(int index)
 {
 	struct sunxi_usbc_hcd *sunxi_usbc = &sunxi_usbc_hcd[index];

arch/arm/include/asm/arch-sunxi/usbc.h

@@ -20,3 +20,4 @@ void sunxi_usbc_enable(int index);
 void sunxi_usbc_disable(int index);
 void sunxi_usbc_vbus_enable(int index);
 void sunxi_usbc_vbus_disable(int index);
+void sunxi_usbc_enable_squelch_detect(int index, int enable);

drivers/usb/musb-new/musb_uboot.c

@@ -1,5 +1,8 @@
 #include <common.h>
 #include <watchdog.h>
+#ifdef CONFIG_ARCH_SUNXI
+#include <asm/arch/usbc.h>
+#endif
 #include <asm/errno.h>
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
@@ -186,8 +189,19 @@ void usb_reset_root_port(void)
 	power &= 0xf0;
 	musb_writeb(mbase, MUSB_POWER, MUSB_POWER_RESET | power);
 	mdelay(50);
+#ifdef CONFIG_ARCH_SUNXI
+	/*
+	 * sunxi phy has a bug and it will wrongly detect high speed squelch
+	 * when clearing reset on low-speed devices, temporary disable
+	 * squelch detection to work around this.
+	 */
+	sunxi_usbc_enable_squelch_detect(0, 0);
+#endif
 	power = musb_readb(mbase, MUSB_POWER);
 	musb_writeb(mbase, MUSB_POWER, ~MUSB_POWER_RESET & power);
+#ifdef CONFIG_ARCH_SUNXI
+	sunxi_usbc_enable_squelch_detect(0, 1);
+#endif
 	host->isr(0, host);
 	host_speed = (musb_readb(mbase, MUSB_POWER) & MUSB_POWER_HSMODE) ?
 			USB_SPEED_HIGH :